This application also incorporates by reference U.S. patent application Ser. Nos. 10/443,954 filed May 23, 2003, 10/854,280 filed May 27, 2004, and 11/113,176 filed Apr. 25, 2005, and relates to a wind powered beat.
The wind powered boat according to the present invention provides a unique mounting structure for a vertical axis wind turbine (“VAWT”), such as a Savonius turbine, or open helix turbine. The VAWT illustrated and described in co-pending application Ser. No. 11/113,176 filed Apr. 25, 2005 is preferred. The mounting structure mounts the VAWT to two or more hulls of a multi-hull watercraft, preferably to the two hulls/pontoons of a catamaran.
The mounting structure provides a sleeve for the shaft of the VAWT, and secure support of the sleeve to the hulls. The mounting structure preferably comprises at least two struts (and desirably exactly two struts) extending from each of at least four points (and desirably exactly four points) on the hulls to the sleeve, and the struts are either directly, or through one or more collars operatively connected to the sleeve. The sleeve, struts, and collars (if any) are preferably made of a strong yet light weight and corrosion resistant material, such as aluminum, titanium, or a number of suitable conventional fiber reinforced plastics. Aluminum rods, tubes, or bars, or materials having strength, corrosion resistance, and weight properties substantially similar to aluminum rods, tubes, or bars, are preferred for the struts.
Operatively connected to the bottom of the sleeve there preferably is a gear box having gears that transmit the rotation of the shaft of the VAWT which extends through the sleeve, to rotation of a generally horizontal axis propeller. Desirable gear ratios of the VAWT shaft to the propeller shaft are preferably between about 1:1 to 5:1, e.g. about 2:1. The gear box may be sealed and contain a lubricant, such as oil, to provide optimum lubrication of the gears.
The mounting structure for the VAWT is preferably mounted adjacent the stern of the watercraft, although it may be mounted adjacent the bow. Alternatively, and preferably two counter-rotating VAWTs with counter-rotating propellers are provided, one adjacent the bow and the other adjacent the stern.
The rudder system must be substantial, that is have a large area and provide significant stability. Also, the one or more rudders desirably have an airfoil configuration (as used on conventional Laser class sailboats) so as to minimize drag and enhance rudder effectiveness. Where the preferred catamaran base is utilized, a rudder is preferably mounted adjacent the stern of each hull, and a single operating lever may be provided. Where a pair of seats are provided for the watercraft, the control lever for the rudders is preferably operatively mounted between the seats and a linkage extends to a first rudder. Then (as is conventional per se for some sailing catamarans, such as many Hobiecat® sailboats) a linkage operatively connects the first rudder to the second rudder, so that they move substantially in tandem.
That is, according to one aspect of the invention a watercraft is provided comprising: at least two spaced hulls; at least one seat mounted on or between the hulls; a vertical axis wind turbine operatively mounted to the hulls aft of the seat; and at least one propeller operatively connected to the wind turbine. The watercraft preferably includes a manual assist [the word “assist” does not imply that the pedal mechanism necessarily performs less than ½ of the work to move the watercraft—under some circumstances it may provide more than ½, or even all, of the motive force for moving the watercraft).
Desirably, the manual assist comprises a pedal driven propeller manual assist operable by someone sitting in a seat. The manual assist propeller is distinct from the propeller(s) operatively connected to the wind turbine(s), and can be used to solely move the watercraft forward, to add to the wind driven propeller's forward movement of the watercraft, or—when pedaled backwards—to move the watercraft backwards. The pedal unit per se may be conventional, that is one used on a conventional Seacycle® (see U.S. Pat. No. 5,011,441).
The propeller or propellers (more than one can be used) driven by the or each VAWT is/are preferably of large diameter and large pitch. For example, particularly for a 12-20 foot catamaran base for the watercraft, if a single propeller for a VAWT is used, that propeller may have a diameter of about 15-22 inches (e.g. about 17-20 inches), and have a highly desirable hydrodynamic configuration. Alternatively, two 15 or 16 inch diameter conventional propellers for the Seacycle® pedal unit may be mounted on the propeller shaft (approximately ninety degrees to each other) operatively connected to the VAWT.
The propeller for the pedal mechanism may be the conventional one sold with the Seacycle® pedal unit.
According to another aspect of the present invention, a wind powered watercraft is provided comprising: At least two hulls, and at least two Savonius or helical vertical axis wind turbines operatively connected to at least one of the hulls, and each wind turbine operatively connected to a substantially horizontal axis propeller. The wind turbines and propellers are constructed so that one wind turbine and one propeller rotate clockwise, and one wind turbine and one propeller rotate counterclockwise.
According to another aspect of the present invention there is provided: a mounting structure for a vertical axis wind turbine (desirably, but not necessarily, mounted on a watercraft) having a rotatable shaft. The mounting structure comprises: a sleeve receiving the shaft with the shaft rotating within the sleeve supported by at least one bearing; and at least two struts extending from at or adjacent each of at least four, stationary with respect to the shaft, mounting points to the sleeve, the struts operatively connected to the sleeve. For example exactly two struts extend from at or adjacent each mounting point to the sleeve, a first of the two struts operatively connected (e.g. by welding or mechanical fasteners, with or without a collar) to the sleeve vertically above the second of the two struts; and the sleeve and struts are made of aluminum or a material characteristically similar to aluminum.
According to another aspect of the invention, in the watercraft according to the invention, and/or of the above mentioned patent applications (or even in land mounted wind turbines such as land mounted VAWTs, although likely not as critical there), a safety mechanism is provided. That is, in order to provide an indication as to when a passenger, operator, or other person, is getting too close to the rotating wind turbine, strips of material may be connected to any suitable radial peripheral portions of the turbine so that the strips of material will contact the person before a solid portion of the turbine does, and provide an indication that care should be taken by the person.
According to this aspect of the invention, a safety mechanism for a rotatable wind turbine (e.g. a vertical axis wind turbine mounted on a watercraft) is provided comprising a plurality of strips of material operatively connected to peripheral portions of the wind turbine so as to rotate with the wind turbine and extend radially outwardly therefrom. Preferably the strips of material are flexible and hang substantially limply when the turbine is not rotating. The strips of material may have an airfoil or isosceles triangle configuration in cross section, and may be of at least two different lengths. At least some of the strips may have a plurality of rupturable bubbles having liquid therein.
It is the primary object of the present invention to provide an effective, relatively simple construction, and safe, wind powered boat. This and other objects of the invention will become clear from a detailed description of the invention, and from the appended claims.